APPARATUS AND METHOD FOR FINISHING A THREE-DIMENSIONAL SURFACE

DESCRIPTION

Field of the invention

The present invention relates to an apparatus for finishing surfaces , in particular surfaces having a complex geometry .

Furthermore , the invention relates to a method for finishing surfaces .

Background of the invention

As known, in order to carry out the operations for finishing surfaces made of di f ferent materials such as pottery, wood, plastic materials , metallic materials , etc . in order to improve their shape, the accuracy of the measurement and their tribological properties , grinding machines or sanding machines are commonly used that are equipped with an abrasive element, typically an abrasive disc .

Normally, the sanding or grinding operations are carried out by hand by a worker who grasps a manual sanding or grinding machine , and moves the abrasive di sc with respect to the surface to be finished . More precisely, in the machines of known type , the abrasive disc is constrained to a support , commonly known as "grinding cup" , which is moved by an electric motor, or by compressed air . Generally, a di fference is made between orbital sander machines , where the abrasive member i s moved, by the support , in order to cause more or less large circular movements, and roto-orbital sander machines, where to the orbital motion a rotating motion is added. In this way, it is possible to carry out a finishing of the worked surfaces of high quality.

Automatic machines are also known which provide a displacement device, for example an anthropomorphic arm, which is able to move the support and, therefore, the abrasive disc which is constrained to it with respect to the surface to be finished. An example of an apparatus of this type is described in EP3107686 in the name of the same Applicant.

The abrasive member can be constrained to the grinding cup, or more in general to the support, in different ways, for example by Velcro, or adhesive tape, or also by means of a threaded connection. Normally, the threaded connection is provided between a threaded blind hole made in the support, and a threaded shaft of which the abrasive element is provided at the face opposite to the face that, in working conditions, exerts the abrasive action. A very common type of threaded connection between support and abrasive disc, usually known in the technical field as "ROLOC" system, is, for example, described in US3562968.

Both in case of manual machines and in case of automatic machines, not all the surfaces can be accurately and precisely finished. In fact, in the case of surfaces having a complex geometry that means comprising one, or more undercut zones, or portions with a different radius of curvature, some portions cannot be reached. In this case, therefore, it is necessary that a worker manually carries out the operation by using different abrasive tools in order to reach by hands the more secluded parts of the worked surface .

However, the aforementioned process is altogether very complex and di f ficult to carry out and is not able to guarantee high qualitative standards obtained for example by the aforementioned automatic machines .

Some apparatuses for f inishing surfaces with the aforementioned drawbacks are for example described in US2006/ 111032 , W02019/ 123310 , US2007 / 135028 and US2013/244547 .

Summary of the invention

It is , therefore , an obj ect of the present invention to provide an apparatus for finishing surfaces , in particular surfaces having a complex geometry, that allows to overcome the aforementioned drawbacks of the prior art solutions .

It i s in particular an obj ect of the present invention to provide a similar apparatus that is highly versatile because able to finish surfaces having geometry that are very di f ferent from one another .

It is also an obj ect of the present invention to provide a method for finishing surfaces , in particular surfaces having a complex geometry, having the aforementioned advantages with respect to the prior art methods .

These and other obj ects are achieved by an apparatus , according to the invention, for finishing a three- dimensional surface having a profile with a predetermined geometry, said apparatus comprising : - a support body configured to removably engage a finishing member ;

- a displacement device configured to move said support body in space according to at least one degree of freedom to exert a finishing action on said three- dimensional surface by said finishing member ;

- a control unit configured to operate said displacement device to move said support body according to said at least one degree of freedom; whose main characteristic is to provide a shaping station at which a raw member having at least one spatial dimension greater than at least one spatial dimension of said profile of said three-dimensional surface to be finished is arranged to be shaped to obtain said finishing member and that said control unit is , furthermore , configured to cause a relative motion according to at least two degrees of freedom of said raw member and of a shaping member at the aforementioned shaping station on the basis of said predetermined geometry of said profile , in such a way to reproduce said predetermined geometry of said profile of said three-dimensional surface to be finished at a determined portion of said raw member and thus to obtain in this way said finishing member comprising at least one portion with an external surface having a profile with a geometry equal , or substantially equal , to the geometry of said profile of said three- dimensional surface to be finished .

Other technical characteristics of the invention and relative embodiments are defined in the dependent claims .

Preferably, the aforementioned support body and the aforementioned shaped abrasive member can be , respectively, provided, at respective engagement surfaces , with respective engagement members configured to move from an engagement configuration to a disengagement configuration, and vice versa .

In particular, the predetermined shape of the aforementioned shaped abrasive member is obtained by a model designed by a design software , for example a CAD software , of the aforementioned surface to be finished .

In an alternative embodiment o f the invention, the aforementioned model can be designed on the basis of the geometry of the surface detected by a detection device , for example a video camera, or an optical device , in particular by a "Kinect" device .

Preferably, the raw member can be made of a material having a hardness lower than the hardness of the material of the aforementioned shaping member .

In particular, the aforementioned raw member can be made of a material selected from the group of :

- felt ;

- sponge ;

- a material based on non-woven synthetic fibres ;

- a polymer of non-woven fibres selected from : cellulose , nylon, or polypropylene ;

- a non-woven material based on synthetic fibres soaked with abrasive granules ;

- a non-woven material based on synthetic fibres soaked with abrasive granules of aluminium oxide and silicon carbide ;

- a non-woven material based on synthetic fibres soaked with abrasive granules of titanium dioxide .

In particular, the aforementioned shaping member can be made of a metallic material .

In a possible embodiment foreseen, the displacement device can be arranged both to move the raw member at the shaping station to obtain the finishing member and to position the finishing member at the surface to be finished and to move the finishing member with respect to the surface to be finished .

Advantageously, the aforementioned finishing member can be a diamond disc . In an alternative embodiment foreseen, the shaping member can have a substantially conical , or cylindrical , shape .

In particular, the raw member can have a substantially prismatic, or cylindrical , shape .

According to another aspect o f the invention, a method for finishing a three-dimensional surface comprises the steps of :

- providing an apparatus for finishing surfaces comprising a support body configured to removably engage a finishing member ;

- moving in space of said support body with respect to said three-dimensional surface to be finished according to at least one degree of freedom to carry out a finishing action on said three-dimensional surface by said finishing member ; whose main characteristic is that is a shaping step is , furthermore , provided to give a determined shape to a raw member having at least one spatial dimension greater than at least one spatial dimension of said profile o f said three-dimensional surface to be finished, in such a way to obtain said finishing member and that said shaping step is carried out by causing a relative motion according at least two degrees of freedom between said raw member and a shaping member in such a way to reproduce said predetermined geometry of said profile of said three- dimensional surface to be finished at a determined portion of said raw member and thus to obtain said finishing member comprising at least one portion with an external surface having a profile with a geometry equal , or substantially equal , to the geometry of said profile o f said three-dimensional surface to be finished .

Brief description of the drawings

The invention will be now illustrated with the following description of an exemplary embodiment thereof , exempli fying but not limitative , with reference to the attached drawings wherein :

Fig . 1 diagrammatically shows a side elevational perspective view of a first embodiment of a three- dimensional surface which can be worked by the apparatus , according to the invention, for finishing surfaces ;

Figures 2 and 3 diagrammatically show, respectively a transverse section view and a perspective view of a shaped finishing member to finish the surface of figure 1 ;

Fig . 4 diagrammatically shows a side elevational perspective view of a first embodiment of a shaping station of the apparatus according to the invention; Fig . 5 diagrammatically shows a side elevational perspective view of a first embodiment of a finishing station provided by the apparatus , according to the invention, for finishing surfaces ;

Figures 6 and 7 diagrammatically show, respectively, a transverse section view and a perspective view of an alternative embodiment of the finishing member of figures 2 and 3 for finishing the surface of figure 1 ;

Fig . 8 diagrammatically shows a side elevational perspective view of the finishing member of figures 6 and 7 used for finishing, at a finishing station, the surface of figure 1 ;

Fig . 9 diagrammatically shows a three-dimensional target surface which represents a portion of a complex surface to be finished;

Figures 10 and 11 diagrammatically show, respectively, a transverse section view and a perspective view of an embodiment of the finishing member obtained by the apparatus according to the invention to finish the surface of figure 9 ;

Fig . 12 shows the finishing member of figure 11 during a working step of the target surface ;

Fig . 13 shows an enlargement of a portion of figure 12 to highlight some characteristics of the apparatus according to the invention;

Fig . 14 diagrammatically shows a front view of another possible profile of a surface that can be worked by the apparatus according to the invention;

Fig . 15 diagrammatically shows a transverse section view of a possible finishing member that can be obtained by the apparatus according to the invention to finish the surface of figure 14 ;

Fig . 16 diagrammatically shows the finishing member of figure 15 during working conditions ;

Fig . 17 diagrammatically shows a front view of another possible profile of a surface that can be worked by the apparatus according to the invention;

Fig . 18 diagrammatically shows a front view of a possible embodiment of a finishing member that can be obtained by the apparatus according to the invention for finishing the surface of figure 17 ;

Fig . 19 diagrammatically shows the finishing member of figure 18 during working conditions ;

Figures from 20 to 22 diagrammatically show side elevational views of some possible alternative embodiments of the shaping member that can be used at the shaping station to give a desired shape to the raw abrasive member;

Figures 23 and 24 diagrammatically show side elevational perspective views of some possible alternative embodiments of the shaping member and the displacement device of the shaping member to give to the raw member a determined shape ;

Fig . 25 diagrammatically shows a side elevational perspective view of a possible embodiment of the displacement device of the abrasive member at the finishing station;

Fig . 26 diagrammatically shows a side elevational perspective view a first embodiment of the engagement members to engage the raw member or the finishing member, and the support body;

Figures 27 and 28 diagrammatically show side elevational perspective views of some embodiments alternative to the embodiment of figure 26 of the engagement members of the raw member, or of the finishing member, to the support body .

Detailed description of some exemplary embodiments of the invention

In the figures 1 and 2 , a first embodiment is diagrammatically shown of the apparatus 1 , according to the invention, for finishing a surface , in particular a three-dimensional surface , 100 having a profile 105 with a predetermined geometry . In particular, the profile 105 can be formed by a plurality of faces , for example 3 faces 101 , 102 , and 103 , oriented in the space one with respect to the other according to predetermined inclinations , for example orthogonal one with respect to another like in the case shown in figure 1 . In general , the profile 105 can be seen as the group of the straight, or curvilinear, segments obtained by cutting the three-dimensional surface 100 , or more precisely a "target portion" of the same , by a determined cutting plane . Therefore , the profile 105 of surface 100 to be worked, in particular to be fini shed, by the apparatus 1 according to the invention, has a complex geometry . In particular , the aforementioned surface 100 to be worked can have a complex geometry which comprises , for example , one or more undercut zones , and/or a plurality of portions with a di f ferent radius of curvature .

In particular, at the shaping station 250 the aforementioned raw member 20 ' can be arranged to be shaped in such a way to make an external surface 26 having a profile 25 with a geometry equal , or substantially equal , to the geometry of at least a first and a second face 101 and 102 , advantageously of at least a first , a second and a third face 101- 103 of profile 105 of the three- dimensional surface 100 to be finished .

As diagrammatically shown, for example in figure 5 , the apparatus 1 comprises a displacement device 40 configured to move a support body 10 in space according to at least one degree of freedom, in particular one translational degree o f freedom ( see for example figures 5 and 19 ) , or at least one translational degree of freedom and one rotational degree of freedom ( see figures 8 , 12 , 13 and 16 ) . In particular, the support body 10 is arranged to engage , advantageously removably, a finishing member 20 to move it with respect to the aforementioned surface 100 to be finished, in particular at a finishing station 150 .

According to the what is provided by the present invention and diagrammatically shown in figure 4 , the apparatus 1 provides at least one shaping station 250 at which a raw member 20 ' , for example of substantially prismatic, or cylindrical , but also spherical , or conical , shape , is arranged to be positioned in order to be shaped in such a way to give it a determined shape . In particular, at the shaping station 250 a shaping member 75 is provided configured to give a determined shape to the raw member 20 ' , in such a way to obtain the aforementioned finishing member 20 . More in particular, the raw member 20 ' has at least one spatial dimension h' greater than at least one spatial dimension h of profile 105 of the three- dimensional surface 100 to be finished, or more precisely of a portion 101 , 102 , or 103 of this . More precisely, the raw member 20 ' and the shaping member 75 are configured to move one with respect to the other according to at least two degrees of freedom in such a way to reproduce the profile 105 of the three-dimensional surface to be finished 100 at a determined portion of the raw member 20 ' and to obtain the finishing member 20 comprising at least one portion with an external surface 26 with a profile 25 having a geometry equal , or substantially equal , to the geometry of profile 105 of the three-dimensional surface 100 to be finished ( see figures 2 , 3 , from 10 to 12 , from 14 to 16 , and from 17 to 19 ) . In particular, the geometry of profile 25 is to be intended as substantially equal to the aforementioned geometry of the surface to be finished i f they di f fer from each other within a predetermined dimensional range .

More precisely, the raw member 20 ' and the shaping member 75 are moved one with respect to the other, in such a way to allow the shaping member 75 to shape the raw member 20 ' , in particular removing the excess material with respect to the desired shape, i . e . the shape with a profile 25 having a geometry equal , or substantially equal , to the profile 105 o f the three-dimensional surface 100 in order to obtain the aforementioned finishing member 20 . This is , therefore , arranged to be positioned, as anticipated above , at the surface to be finished 100 and to be moved with respect to it in order to carry out a predetermined finishing action, for example a sanding, a polishing, or a grinding, action .

More precisely, in the embodiments shown in the figures 5 and 19 , i f during the working of surface 100 , the finishing member 20 is arranged to be translated by the displacement device 40 with respect to the surface 100 , the aforementioned profile 105 is duplicated on a side of the raw member 20 ' ( in figure 2 the right side , in figure 19 the lower side ) .

Instead, i f the finishing member 20 , during the finishing action, is arranged to be rotated about its axis 120 by the displacement device 40 , the aforementioned profile 105 of surface 100 to be finished is made on the raw member 20 ' in such a way to be axially symmetric with respect to the aforementioned axis 120 ( see figures from 6 to 8 and from 10 to 13 ) .

In a first embodiment o f the invention, diagrammatically shown in figure 4 , the raw member 20 ' can be positioned at the shaping station 250 and in case moved with respect to the shaping member 75 , by a second displacement device 140 , i . e . by a displacement device which is di f ferent from the displacement device 40 . Therefore , in this case, between the shaping station 250 and the finishing station 150 a removal station can be , advantageously, provided, that is not shown in the figure for simplicity, to remove the finishing member 20 from the second displacement device 140 , and an application station, which is , also this , not shown in the figure for simplicity, at which the finishing member 20 is engaged to the support body 10 of the displacement device 40 arranged to move it with respect to the surface 120 to be finished . In a preferred alternative embodiment of the invention, instead, the displacement device 40 moves the raw member 20' at the shaping station 250 and, in case, moves the raw member 20' same with respect to the shaping member 75 in order to obtain the finishing member 20.

In particular, with reference, for example, to figure 4, at the shaping station 250, it is possible to provide a secondary displacement device 85 configured to move, or simply to support, the shaping member 75, during the aforementioned shaping step of the raw member 20' . In particular, during the aforementioned shaping step, at least one between the raw member 20' and the shaping member 75, respectively by the displacement device 40 or 140, and the secondary displacement device 85, can be moved one with respect to the other according to at least two degrees of freedom, for example in such a way to cause at least one relative rotation, or at least one relative translation, or a combination of movements comprising at least one translation and at least one rotation.

In a preferred embodiment, the shaping member 75 can be a tool configured to remove material from the raw member 20' by mechanical contact. In particular, as shown in the figures 4, 20 and 21, the shaping member 75 can be a diamond disc, or a cutter having for example a conical shape (figure 24) , or a cylindrical shape, case that is not shown in the figure for simplicity, or even, a cutting blade, advantageously, shaped (figure 20) .

Alternatively, the shaping member 75 can be a device for subjecting the raw member 20' to a specific treatment, in particular a thermal treatment and, therefore, able to remove the excess material with respect to the aforementioned predetermined shape with no mechanical contact with it . For example , as diagrammatically shown in figure 22 , the device for carrying out the thermal treatment 75 can be configured to emit a laser beam .

Advantageously, the support body 10 and the finishing member 20 can be , respectively, provided, at respective engagement surfaces 13 and 33 , with engagement members 15 and 35 configured to move , from an engagement configuration to a disengagement configuration, and vice versa .

In particular, in an embodiment foreseen, the engagement members 15 and 35 , can be arranged to carry out a snap engagement , for example by respective shaped surfaces ( figure 26 ) . In this case , the engagement members 15 and 35 can comprise , respectively, at least one protrusion and at least one recess , or vice versa .

In a further alternative embodiment , the finishing member 20 can be constrained to the support body, by a threaded coupling ( figure 28 ) . For example , the threaded coupling can be provided between a threaded blind hole 15 ( see for example figure 26 ) made in the support body 10 and a threaded shaft 35 of which the finishing member 20 is provided with, at the face oppos ite to the face , which, in working conditions , exerts the finishing action, in particular an abrasive action . In a further alternative embodiment , the engagement members 15 and 35 can comprise , respectively, first and second portions of strip having predetermined si ze and arranged to removably mutually engage with each other, also called, respectively, "male Velcro" and "female Velcro".

In particular, once that the finishing member 20 has been shaped as described above, it can be seen as a "three-dimensional finishing member". More in particular, the finishing member 20 can have an external abrasive surface obtained starting from the aforementioned raw member 20' , having a substantially cylindrical, or substantially prismatic, or again a substantially conical, geometry, and reproducing on a portion of the external surface 26 a portion having a profile 25 equal, or substantially equal, al profile 105 of the surface to be finished. In particular, the external surface 26 has a profile having a shape that is complementary to the shape of profile 105. The finishing member 20 will have, therefore, in general, one, or more, protruding portions and one, or more, recessed portions, which match with the profile 105 of the three-dimensional surface 100 to be finished (see figures from 1 to 3, from 6 to 7, from 10 to 12, and from 14 to 19) . In particular, the geometric shapes that can be obtained with the apparatus 1 according to the invention can be highly complex, in particular comprising at least one undercut zone and/or portions with a different radius of curvature (see for example figure 13) . This allows to reach also the portions of the worked surface 100, that cannot be reached, or however that can be very difficultly reached by the abrasive discs of prior art, or by the three-dimensional abrasive members of the prior art which are not shaped and which have simpler geometries, in particular cylindrical, or prismatic, and, furthermore, to work at the same time more faces, for example 3 faces 101- 103 in the case of figures from 1 to 3 , and in the case that is shown in the figures from 6 to 8 , but al so 4 , or more faces , faces 101- 104 as in the case of figures 12 and 13 .

In a preferred embodiment diagrammatically shown in the figures 12 , and from 23 to 25, the displacement device 40 can be an anthropomorphic robot and to be configured to move in space the support body 10 and, therefore , the finishing member 20 , and in case also the raw member 20 ' , according to at least 5 degrees of freedom, for example according to 6 degrees of freedom . The possibility is , however, also provided that the displacement device 40 is configured to move the support body 10 according to one or more degrees of translational freedom, or one or more degrees of rotational freedom, or according to a combination of movements comprising at least one translational degree of freedom and one rotational degree of freedom and altogether according to a number of degrees of freedom comprised between 1 and 6 . In particular, the displacement device 40 can be configured to cause at least a moto of rotation of the support body 10 about a rotation axis 110 with respect to a working head 50 . The possibility is also provided that the apparatus 1 is of roto-orbital type . Therefore , in this case , the displacement device 40 can be configured to move the support body 10 , in such a way that this describes an eccentric orbit with respect to the axis of the working head 50 .

In a further alternative embodiment , the displacement device 40 can be arranged to translate the support body 10 , and, therefore , the finishing member 20 , with respect to the surface to be finished 100 , for example according to a back-and- forth motion, in particular to cause the finishing member 20 to oscillate with respect to the surface to be finished 100 .

In a possible embodiment of the invention, the shape of the finishing member 20 can be made on the basis of a model designed by a design software , in particular a CAD software . In particular , the aforementioned geometry can be obtained by the design for carrying out the surface 100 , or can be designed on the basis of measurements of surface 100 , or, even, can be obtained by a detection device , not shown in figure for simplicity, configured to detect the geometry of the profile 105 of the surface 100 to be finished .

In particular, in the case that the aforementioned shaping operation is carried out by mechanical contact between the raw member 20 ' and the shaping member 75 , the material of the raw member 20 ' will have a hardness lower than the hardness of the material of the shaping member 75.

For example , the raw member 20 ' can be made of a material selected between : felt , sponge , a material formed by non-woven synthetic fibres , in particular nonwoven fabric, a polymer formed by non-woven fibres selected from the group of : cellulose , nylon, or polypropylene , a material formed by non-woven synthetic fibres impregnated with abrasive granules , a material formed by non-woven synthetic fibres impregnated with abrasive granules o f aluminium oxide and silicon carbide , a material formed by non-woven synthetic fibres impregnated with abrasive granules of titanium dioxide. Preferably, therefore, the finishing member 20 can be an abrasive member, but in general can be a member used to distribute an abrasive compound, for example an abrasive paste, on the surface to be finished 100. In both the cases, however, the finishing member 20 is moved, in particular by the displacement device 40, against the surface to be finished 100 to produce, preferably, an abrasive action.

The shaping member 75 can be, advantageously, made of a metallic material. In particular, the shaping member 75 can be a diamond disc, or can have a substantially cylindrical, or substantially conical, shape.

In an embodiment of the invention, the apparatus 1 can comprise a check station, which is not shown in the figure for simplicity, at which the presence is verified of the finishing member 20 at the support body 10. In particular, the aforementioned check station can be positioned between the removal station and the application station, to verify that the finishing member 20 is correctly removed before applying a new raw member 20' on the support body 10.

As diagrammatically shown in the figures 23 and 24 a control unit 300 can be, furthermore, provided configured to control the displacement device 40, and/or 140, of the raw abrasive member 20' , and/or the secondary displacement device 85 of the shaping member 75, at the shaping station 250, in such a way to control the shaping step of the raw member 20' .

In particular, the control unit 300 can be configured to cause a relative motion according to at least two degrees of freedom between the aforementioned raw member 20' and the aforementioned shaping member 75. More in particular, the control unit 300 can be configured to operate on the basis of the predetermined geometry of profile 105 the displacement device 40 and/or the second displacement device 140 and/or the aforementioned secondary displacement device 85 at the shaping station 250 in such a way to reproduce the geometry of the profile 105 of the three-dimensional surface 100 to be finished at a predetermined portion of the raw member 20' in order to obtain, this way, the finishing member 20, preferably comprising at least one portion with an external surface 26 having a profile 25 with a geometry equal, or substantially equal, to the geometry of said profile 105 of the three-dimensional surface 100 to be finished.

For example, the control unit 300 can be arranged to elaborate the data deriving from the model in digital format, for example the aforementioned CAD model, of the surface to be finished, or by the detection device to operate the displacement device 40, or the second displacement device 140, of the raw member 20' , and/or the secondary displacement device 85 of the shaping member 75, accordingly.

The foregoing description of a specific embodiment will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such an embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.